Osteoporosis

Osteoporosis, cancer and nutrition

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Cancer patients have a greater risk of developing osteoporosis. Dietitian, Annica Rust, informs us how to counteract this risk with adequate calcium and vitamin D intake.

What is osteoporosis?

Osteoporosis is characterised by low bone density and quality. This leads to a weak skeleton with an increased risk of a fracture; particularly in the spine, wrists, hips and upper arms.2 

Your body will always try to maintain homeostasis (optimal functioning, such as body temperature and fluid balance) or normal blood calcium levels. Therefore, no sign of osteoporosis will be exhibited until the advanced stage of a broken bone.1,2 

According to statistics, documented by the National Osteoporosis Foundation of South Africa (NOFSA), 20% of all fracture victims will die within a year and 50% will never regain independency.4 

Risk factors for developing osteoporosis include: age (older than 60 years), cigarette smoking, oestrogen depletion from menopause, ethnicity (White/Asian), excessive alcohol and caffeine intake, female gender, a family history of osteoporosis, inadequate calcium and vitamin D intake, sedentary lifestyle, prolonged use of certain medicines and being underweight.3

Greater risk for a cancer patient

Patients with cancer will have a greater risk for developing osteoporosis due to the effects of cancer cells on the skeleton and the deleterious effects of cancer treatment on bone cells as below.5 

  • The cancer cells may stimulate the production of osteoclasts (cells that break down bone) which can increase the risk of osteoporosis.
  • Cancer treatments, such as chemotherapy, which induces ovarian failure which in turn causes a decrease in oestrogen. Oestrogen deprivation ultimately can lead to bone loss. 
  • The use corticosteroids which affects vitamin D metabolism which in turn can lower calcium absoption.1

Much needed nutrients

Calcium, phosphates, vitamin D, vitamin K and magnesium are essential for normal bone structure and function. Calcium and vitamin D are considered the two most important nutrients in the nutritional management of osteoporosis.3 Calcium is important to build and maintain strong bones while vitamin D assists with the absorption of calcium.3

NOFSA recommendations

Vitamin D

NOFSA recommends 800-1000IU vitamin D (800IU vitamin D prophylactic dose).2 

To achieve adequate amount of vitamin D synthesis, a person should be exposed to the sun two to three times per week, between the hours of 11:00 – 15:00 for 10-15 minutes, exposing 25% of the body (arms/legs). Sunscreen can reduce vitamin D syntheses up to 95-99%. Please still be sun safe!

The amount of sunlight exposure required to produce vitamin D depends on the skin type (dark skin types need to be exposed for longer).3

Calcium

NOFSA recommends a daily calcium intake of 1000-1200mg for the treatment of osteoporosis. If dietary intake is insufficient, 500-600mg of elemental calcium (in the form of a supplement) is recommended. 

Dairy products are high in calcium. Consuming three dairy products per day will make it possible to achieve NOFSA’s recommendation.2

If you are lactose intolerant, consider replacing dairy with lactose-free dairy products or use lactase tablets (enzymes that breaks down lactose) when consuming dairy products. Yoghurt is often tolerated because the lactose is broken down in the fermentation process. 

Dairy products aren’t the only source of calcium. Calcium can also be found in green leafy vegetables and in the bones of sardines. Green leafy vegetables are lower in calcium and a larger portion needs to be consumed to reach your recommended dietary allowance.3 Last but not least, currently there is not enough scientific evidence to support the association between dairy consumption and an increased cancer risk.6,7,8 The benefits of consuming dairy products currently outweigh the potential risks. 

References

  1. International Osteoporosis foundation: https://www.iofbonehealth.org/what-is-osteoporosis
  2. National Osteoporosis Foundation of South Africa: https://osteoporosis.org.za/information/what-is-it/
  3. Mahan, L.K. & Raymond, J.L. (eds).2017. Krause’s food and the nutrition care process. 14th ed. St Louis. MO: Elsevier Saunders.
  4. National Osteoporosis Foundation of South Africa (NOFSA). The 2017 revised NOFSA guidelines. 2017. Journal of Endocrinology, Metabolism and Diabetes of South Africa:22(1).
  5. Drake, M.T. 2013. Osteoporosis and Cancer. Curr Osteoporos Rep:11(3).
  6. American Institute for Cancer Research. 2018. Meat, fish and dairy products and the risk of cancer.
  7. Nilssona, L.M., Winkvistb, A., Esbergc, A., Janssona, J., Wennberga, P., van Guelpend, P. & Johanssona, I. Dairy Products and Cancer Risk in a Northern Sweden Population. Nutrition & Cancer:72(3).
  8. Chen, L., Li, M. & Li, H. 2019. Milk and yogurt intake and breast cancer risk A meta-analysis. Medicine:98(12).
  9. Rediscover Dairy: https://www.rediscoverdairy.co.za/
Annica Rust is a registered dietitian practicing at the Breast Care Unit in Netcare Milpark Hospital as well as in Bryanston. She assists with medical nutritional therapy for cancer prevention, treatment, survivorship and palliation. She gives individualised nutritional care to prevent or reverse nutrient deficiencies, nutrition-related side effects and malnutrition to maximise quality of life.

MEET THE EXPERT – Annica Rust

Annica Rust is a registered dietitian practicing at the Breast Care Unit in Netcare Milpark Hospital as well as in Bryanston. She assists with medical nutritional therapy for cancer prevention, treatment, survivorship and palliation. She gives individualised nutritional care to prevent or reverse nutrient deficiencies, nutrition-related side effects and malnutrition to maximise quality of life.

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